#include "DHT.h"
#define DHTPIN 32
#define DHTTYPE DHT22
#define LDRPIN 33
#define BTNPIN 4

#define BIT_PRINT_SENSOR_DATA	( 1 << 0 )

DHT dht(DHTPIN, DHTTYPE);

static hw_timer_t *readSensorTimer = NULL;
volatile float h, t, lux;
EventGroupHandle_t evt;
static const uint16_t timer_divider = 5;
static const uint32_t clock_freq = 1000000;
uint64_t lastDebounceTime = 0;
static uint8_t debounceDelay = 100;



void IRAM_ATTR readSensors() {
  h = dht.readHumidity();
  t = dht.readTemperature();
  // if (isnan(h) || isnan(t)) {
  //   Serial.println(F("Failed to read from DHT sensor!"));
  //   return;
  // }

  const float GAMMA = 0.7;
  const float RL10 = 50;
  // int analogValue = analogRead(LDRPIN);  // Crashes on hardware interrupt
  // float voltage = analogValue / 4095. * 5;
  // float resistance = 2000 * voltage / (1 - voltage / 5);
  // lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));

  xEventGroupSetBits(
    evt,    /* The event group being updated. */
    BIT_PRINT_SENSOR_DATA
  );/* The bits being set. */
}

void handleButtonPress() {
  if ((millis() - lastDebounceTime) > debounceDelay) {
    xEventGroupSetBits(
      evt,    /* The event group being updated. */
      BIT_PRINT_SENSOR_DATA
    );/* The bits being set. */
    lastDebounceTime = millis();
  }
}

void printSensorData(void *m) {
  while (1) {
    EventBits_t uxBits = xEventGroupWaitBits(
                           evt,   /* The event group being tested. */
                           BIT_PRINT_SENSOR_DATA, /* The bits within the event group to wait for. */
                           pdTRUE,        /* Should be cleared before returning. */
                           pdFALSE,       /* Don't wait for both bits, either bit will do. */
                           portMAX_DELAY
                         );
    Serial.println("print sensor data");

    if ((uxBits & BIT_PRINT_SENSOR_DATA) != 0) {
      Serial.printf("Humidity: %.2f\n", h);
      Serial.printf("Temperature: %.2f\n", t);
    }
  }
}

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(BTNPIN, INPUT_PULLUP);

  /* Attempt to create the event group. */
  evt = xEventGroupCreate();

  /* Was the event group created successfully? */
  if (evt == NULL) {
    /* The event group was not created because there was insufficient
       FreeRTOS heap available. */
    Serial.println(F("Failed to create event group!"));
  }

  readSensorTimer = timerBegin(clock_freq); 
  timerAttachInterrupt(readSensorTimer, &readSensors); 
  timerAlarm(readSensorTimer, clock_freq * timer_divider, true, 0);

  attachInterrupt(digitalPinToInterrupt(BTNPIN), handleButtonPress, FALLING);

  TaskHandle_t taskPrintSensorData = NULL;
  xTaskCreate(printSensorData, "Print Sensor Data", 4094, NULL, 1, &taskPrintSensorData);
  dht.begin();
}

void loop() {
  delay(10);
}